1. Technical Field
The present invention relates to a resistive touch screen.
2. Description of the Related Art
Alongside the growth of computers using digital technology, devices assisting the computers have also been developed, and personal computers, portable transmitters and other personal information processors execute processing of text and graphics using a variety of input devices such as a keyboard, a mouse and so on.
While the rapid advancement of the information-based society has been widening the use of computers more and more, there have been occurring the problems of it being difficult TO efficiently operate products using only the keyboard and mouse as being responsible for the input device function. Thus, the demand for a device which is simple, does not malfunction, and has the capability to input easily is increasing.
Furthermore, current techniques for input devices exceed the level of fulfilling general functions and thus are progressing towards techniques related to high reliability, durability, innovation, designing and manufacturing. To this end, a touch screen has been developed as an input device capable of inputting information such as text and graphics.
The touch screen is mounted on the display surface of an image display device such as an electronic organizer, a flat panel display including a liquid crystal display (LCD), a plasma display panel (PDP), an electroluminescence (El) element or the like, or a cathode ray tube (CRT), so that a user selects the information desired while viewing the image display device.
The touch screen is classifiable as a resistive type, a capacitive type, an electromagnetic type, a surface acoustic wave (SAW) type, and an infrared type. The type of touch screen selected is one that is adapted for an electronic product in consideration of not only signal amplification problems, resolution differences and the degree of difficulty of designing and manufacturing technology but also in light of optical properties, electrical properties, mechanical properties, resistance to the environment, input properties, durability and economic benefits of the touch panel. In particular, resistive and capacitive types are prevalently used.
Among others, the resistive touch screen is generally manufactured having a structure in which an upper film and a lower substrate on which transparent electrodes are coated are opposite to each other, having a dot spacer therebetween. Reviewing the driving process of the resistive touch screen, when the upper film is touched, it is bent to allow the transparent electrodes coated on the upper film and the lower substrate, respectively, to come in contact with each other, such that the voltage applied to the transparent electrodes is changed. A touched position is sensed by measuring the changes in the voltage. The resistive touch screen has a simple structure, such that it can be easily manufactured at low manufacturing costs and can be reduced in size.
However, in the resistive touch screen according to the related art, the dot spacer is formed on the transparent electrode of the lower substrate. Therefore, when the upper film is drooped, undesirable contact may occur between the transparent electrode on the upper film and the transparent electrode on the lower substrate, having the dot spacer therebetween. In order to solve the problem, there has been proposed to form the dot spacer on the transparent electrode of the upper film.
However, the upper film is bent whenever it is touched. Therefore, when the dot spacer is formed on the transparent electrode of the upper film, stress is applied to the upper surface edge of the dot spacer that is directly fixed to the transparent electrode, causing a problem that the dot spacer becomes detached from the transparent electrode.